#pragma once

/// @file userver/storages/mongo/collection.hpp
/// @brief @copybrief storages::mongo::Collection

#include <memory>
#include <optional>
#include <string>
#include <type_traits>
#include <vector>

#include <userver/formats/bson/document.hpp>
#include <userver/formats/bson/value.hpp>
#include <userver/storages/mongo/bulk.hpp>
#include <userver/storages/mongo/cursor.hpp>
#include <userver/storages/mongo/operations.hpp>
#include <userver/storages/mongo/write_result.hpp>

USERVER_NAMESPACE_BEGIN

namespace storages::mongo {

namespace impl {
class CollectionImpl;
}  // namespace impl

/// @brief MongoDB collection handle, the main way to operate with MongoDB.
///
/// Usually retrieved from storages::mongo::Pool
///
/// ## Example:
///
/// @snippet storages/mongo/collection_mongotest.hpp  Sample Mongo usage
class Collection {
public:
    /// @cond
    // For internal use only.
    explicit Collection(std::shared_ptr<impl::CollectionImpl>);
    /// @endcond

    /// @brief Returns the number of documents matching the query
    /// @warning Unless explicitly overridden, runs CountApprox for empty filters
    /// @see options::ForceCountImpl
    template <typename... Options>
    size_t Count(formats::bson::Document filter, Options&&... options) const;

    /// @brief Returns an approximated count of all documents in the collection
    /// @note This method uses collection metadata and should be faster
    template <typename... Options>
    size_t CountApprox(Options&&... options) const;

    /// Performs a query on the collection
    template <typename... Options>
    Cursor Find(formats::bson::Document filter, Options&&... options) const;

    /// Retrieves a single document from the collection
    template <typename... Options>
    std::optional<formats::bson::Document> FindOne(formats::bson::Document filter, Options&&... options) const;

    /// Inserts a single document into the collection
    template <typename... Options>
    WriteResult InsertOne(formats::bson::Document document, Options&&... options);

    /// Inserts multiple documents into the collection
    template <typename... Options>
    WriteResult InsertMany(std::vector<formats::bson::Document> documents, Options&&... options);

    /// @brief Replaces a single matching document
    /// @see options::Upsert
    template <typename... Options>
    WriteResult ReplaceOne(formats::bson::Document selector, formats::bson::Document replacement, Options&&... options);

    /// @brief Updates a single matching document
    /// @see options::Upsert
    template <typename... Options>
    WriteResult UpdateOne(formats::bson::Document selector, formats::bson::Document update, Options&&... options);

    /// @brief Updates all matching documents
    /// @see options::Upsert
    template <typename... Options>
    WriteResult UpdateMany(formats::bson::Document selector, formats::bson::Document update, Options&&... options);

    /// Deletes a single matching document
    template <typename... Options>
    WriteResult DeleteOne(formats::bson::Document selector, Options&&... options);

    /// Deletes all matching documents
    template <typename... Options>
    WriteResult DeleteMany(formats::bson::Document selector, Options&&... options);

    /// @brief Atomically updates a single matching document
    /// @see options::ReturnNew
    /// @see options::Upsert
    template <typename... Options>
    WriteResult FindAndModify(
        formats::bson::Document query,
        const formats::bson::Document& update,
        Options&&... options
    );

    /// Atomically removes a single matching document
    template <typename... Options>
    WriteResult FindAndRemove(formats::bson::Document query, Options&&... options);

    /// Drop collection
    template <typename... Options>
    void Drop(Options&&... options);

    /// Efficiently executes multiple operations in order, stops on error
    template <typename... Options>
    operations::Bulk MakeOrderedBulk(Options&&... options);

    /// Efficiently executes multiple operations out of order, continues on error
    template <typename... Options>
    operations::Bulk MakeUnorderedBulk(Options&&... options);

    /// @brief Executes an aggregation pipeline
    /// @param pipeline an array of aggregation operations
    /// @param options see @ref storages::mongo::options
    template <typename... Options>
    Cursor Aggregate(formats::bson::Value pipeline, Options&&... options);

    /// @brief Retrieves distinct values for a specified field
    /// @param field name of the field for which to return distinct values
    /// @param options see @ref storages::mongo::options
    template <typename... Options>
    std::vector<formats::bson::Value> Distinct(std::string field, Options&&... options) const;

    /// @brief Retrieves distinct values for a specified field with a query filter
    /// @param field name of the field for which to return distinct values
    /// @param filter query that specifies the documents from which to retrieve distinct values
    /// @param options see @ref storages::mongo::options
    template <typename... Options>
    std::vector<formats::bson::Value> Distinct(std::string field, formats::bson::Document filter, Options&&... options)
        const;

    /// Get collection name
    const std::string& GetCollectionName() const;

    /// @name Prepared operation executors
    /// @{
    size_t Execute(const operations::Count&) const;
    size_t Execute(const operations::CountApprox&) const;
    Cursor Execute(const operations::Find&) const;
    std::vector<formats::bson::Value> Execute(const operations::Distinct&) const;
    WriteResult Execute(const operations::InsertOne&);
    WriteResult Execute(const operations::InsertMany&);
    WriteResult Execute(const operations::ReplaceOne&);
    WriteResult Execute(const operations::Update&);
    WriteResult Execute(const operations::Delete&);
    WriteResult Execute(const operations::FindAndModify&);
    WriteResult Execute(const operations::FindAndRemove&);
    WriteResult Execute(operations::Bulk&&);
    Cursor Execute(const operations::Aggregate&);
    void Execute(const operations::Drop&);
    /// @}
private:
    std::shared_ptr<impl::CollectionImpl> impl_;
};

template <typename... Options>
size_t Collection::Count(formats::bson::Document filter, Options&&... options) const {
    operations::Count count_op(std::move(filter));
    (count_op.SetOption(std::forward<Options>(options)), ...);
    return Execute(count_op);
}

template <typename... Options>
size_t Collection::CountApprox(Options&&... options) const {
    operations::CountApprox count_approx_op;
    (count_approx_op.SetOption(std::forward<Options>(options)), ...);
    return Execute(count_approx_op);
}

namespace impl {

template <typename Option, typename... Options>
using HasOptionHelper = std::disjunction<std::is_same<std::decay_t<Options>, Option>...>;

template <typename Option, typename... Options>
static constexpr bool kHasOption = HasOptionHelper<Option, Options...>::value;

}  // namespace impl

template <typename... Options>
Cursor Collection::Find(formats::bson::Document filter, Options&&... options) const {
    operations::Find find_op(std::move(filter));
    (find_op.SetOption(std::forward<Options>(options)), ...);
    return Execute(find_op);
}

template <typename... Options>
std::optional<formats::bson::Document> Collection::FindOne(formats::bson::Document filter, Options&&... options) const {
    static_assert(
        !(std::is_same<std::decay_t<Options>, options::Limit>::value || ...),
        "Limit option cannot be used in FindOne"
    );
    auto cursor = Find(std::move(filter), options::Limit{1}, std::forward<Options>(options)...);
    if (cursor.begin() == cursor.end()) {
        return {};
    }
    return *cursor.begin();
}

template <typename... Options>
WriteResult Collection::InsertOne(formats::bson::Document document, Options&&... options) {
    operations::InsertOne insert_op(std::move(document));
    (insert_op.SetOption(std::forward<Options>(options)), ...);
    return Execute(insert_op);
}

template <typename... Options>
WriteResult Collection::InsertMany(std::vector<formats::bson::Document> documents, Options&&... options) {
    operations::InsertMany insert_op(std::move(documents));
    (insert_op.SetOption(std::forward<Options>(options)), ...);
    return Execute(insert_op);
}

template <typename... Options>
WriteResult Collection::ReplaceOne(
    formats::bson::Document selector,
    formats::bson::Document replacement,
    Options&&... options
) {
    operations::ReplaceOne replace_op(std::move(selector), std::move(replacement));
    (replace_op.SetOption(std::forward<Options>(options)), ...);
    return Execute(replace_op);
}

template <typename... Options>
WriteResult Collection::UpdateOne(
    formats::bson::Document selector,
    formats::bson::Document update,
    Options&&... options
) {
    operations::Update update_op(operations::Update::Mode::kSingle, std::move(selector), std::move(update));
    (update_op.SetOption(std::forward<Options>(options)), ...);
    return Execute(update_op);
}

template <typename... Options>
WriteResult Collection::UpdateMany(
    formats::bson::Document selector,
    formats::bson::Document update,
    Options&&... options
) {
    operations::Update update_op(operations::Update::Mode::kMulti, std::move(selector), std::move(update));
    (update_op.SetOption(std::forward<Options>(options)), ...);
    return Execute(update_op);
}

template <typename... Options>
WriteResult Collection::DeleteOne(formats::bson::Document selector, Options&&... options) {
    operations::Delete delete_op(operations::Delete::Mode::kSingle, std::move(selector));
    (delete_op.SetOption(std::forward<Options>(options)), ...);
    return Execute(delete_op);
}

template <typename... Options>
WriteResult Collection::DeleteMany(formats::bson::Document selector, Options&&... options) {
    operations::Delete delete_op(operations::Delete::Mode::kMulti, std::move(selector));
    (delete_op.SetOption(std::forward<Options>(options)), ...);
    return Execute(delete_op);
}

template <typename... Options>
WriteResult Collection::FindAndModify(
    formats::bson::Document query,
    const formats::bson::Document& update,
    Options&&... options
) {
    operations::FindAndModify fam_op(std::move(query), update);
    (fam_op.SetOption(std::forward<Options>(options)), ...);
    return Execute(fam_op);
}

template <typename... Options>
WriteResult Collection::FindAndRemove(formats::bson::Document query, Options&&... options) {
    operations::FindAndRemove fam_op(std::move(query));
    (fam_op.SetOption(std::forward<Options>(options)), ...);
    return Execute(fam_op);
}

template <typename... Options>
void Collection::Drop(Options&&... options) {
    operations::Drop drop_op;
    (drop_op.SetOption(std::forward<Options>(options)), ...);
    return Execute(drop_op);
}

template <typename... Options>
operations::Bulk Collection::MakeOrderedBulk(Options&&... options) {
    operations::Bulk bulk(operations::Bulk::Mode::kOrdered);
    (bulk.SetOption(std::forward<Options>(options)), ...);
    return bulk;
}

template <typename... Options>
operations::Bulk Collection::MakeUnorderedBulk(Options&&... options) {
    operations::Bulk bulk(operations::Bulk::Mode::kUnordered);
    (bulk.SetOption(std::forward<Options>(options)), ...);
    return bulk;
}

template <typename... Options>
Cursor Collection::Aggregate(formats::bson::Value pipeline, Options&&... options) {
    operations::Aggregate aggregate(std::move(pipeline));
    (aggregate.SetOption(std::forward<Options>(options)), ...);
    return Execute(aggregate);
}

template <typename... Options>
std::vector<formats::bson::Value> Collection::Distinct(std::string field, Options&&... options) const {
    operations::Distinct distinct_op(std::move(field));
    (distinct_op.SetOption(std::forward<Options>(options)), ...);
    return Execute(distinct_op);
}

template <typename... Options>
std::vector<formats::bson::Value> Collection::Distinct(
    std::string field,
    formats::bson::Document filter,
    Options&&... options
) const {
    operations::Distinct distinct_op(std::move(field), std::move(filter));
    (distinct_op.SetOption(std::forward<Options>(options)), ...);
    return Execute(distinct_op);
}

}  // namespace storages::mongo

USERVER_NAMESPACE_END
